Any diver with a certain experience searching for opisthobranchs in the Mediterranean Sea or NE Atlantic could tell you that, sometimes, it is pretty difficult to tell apart which species of pink “flabellina” you are looking at.
It’s not really that difficult, as long as you know what to look at in order to differentiate them. Here we include the main traits of the most common species:
Flabellina affinis has the following characteristics:
- The distal end of cerata are always colored purple with a white cnidosac on the tip. The rest of the cerata are transparent and allow to see the reddish brown digestive gland inside.
- The cerata are joined in groups emerging from pods growing on the animal’s body.
- Rhinophores have many tight ringed lamellae.
Flabellina affinis by Miquel Pontes
Paraflabellina ischitana has the following characteristics:
- Cerata are transparent and allow to see the brown to orange digestive gland inside, and have a white cnidosac on the tip. No purple tips as in Flabellina affinis.
- The cerata are joined in groups emerging from pods growing on the animal’s body.
- Rhinophores have some loosely ringed lamellae.
Paraflabellina ischitana by Miquel Pontes
Edmundsella pedata has the following characteristics:
- Cerata are transparent and allow to see the brown to orange digestive gland inside, and have a white cnidosac on the tip. No purple tips as in Flabellina affinis.
- The cerata grow directly on the animal’s body, without the pods found in Flabellina affinis or Paraflabellina ischitana.
- Rhinophores are smooth or wrinkled, but clearly without the ringed lamellae as in Flabellina affinis or Paraflabellina ischitana.
Edmundsella pedata by Miquel Pontes
Piseinotecus soussi has the following characteristics:
- Cerata are transparent and allow to see the brown to orange digestive gland inside, and have a white cnidosac on the tip. There is a variable ammount of white dots sprayed on the ceratal surface which are absent in Edmundsella pedata. No purple tips as in Flabellina affinis.
- The cerata grow directly on the animal’s body, without the pods found in Flabellina affinis or Paraflabellina ischitana.
- Rhinophores are smooth or wrinkled, but clearly without the ringed lamellae as in Flabellina affinis or Paraflabellina ischitana. There is a variable ammount of white dots sprayed on the rhinophoral surface which are absent in the other species.
- There are internal physiological differences that classify this species in the Piseinotecus genus, but we only state here the traits visible to a SCUBA diver.
Piseinotecus soussi by Enric Madrenas
Contact us if you still have doubts with a species you found.
